In a synchronous optical network (“SONET”) or synchronous digital hierarchy (“SDH”) network element (“NE”), traffic flows from ingress line cards (“sources”) to egress line cards (“destinations”) across a switch fabric. Switch fabrics generally fall into one of two categories. The first category is circuit switching. For circuit switching, a fixed or static connection or path is established for the duration of the transmission. For such static connection traffic (“static traffic”), the basic switching element is typically in terms of bytes of data. The second category is dynamic switching. For dynamic switching, the connection or path is created dynamically. For such dynamic connection traffic (“dynamic traffic”), the basic switching element is usually in terms of packets of data that typically may take different routes to get to their destination.
The architectures of circuit switching and dynamic switching usually lend themselves to different applications. Therefore, their implementations are usually very different. In certain applications, however, it is desirable to accommodate both types of traffic through the switch fabric of a SONET/SDH NE.